The Tula Valley receives untreated wastewater from Mexico City for agricultural irrigation, half of which infiltrates to aquifers from where drinking water is extracted. Samples of wastewater and infiltrated water from three areas of the valley were analyzed for microorganisms, organic micropollutants, and some basic parameters. Concentrations of microorganisms in the infiltrated water were generally very low but the incidence of fecal coliforms (present in 68% of samples), somatic bacteriophages (36%), Giardia spp. (14%), and helminth eggs (8%) suggested a health risk. Organic micropollutants, often present at high concentrations in the wastewater, were generally absent from the infiltrated water except carbamazepine which was in 55% of samples (up to 193 ng/L). There was no correlation between carbamazepine concentrations and the presence of microorganisms but highest concentrations of carbamazepine and boron coincided. A treatment such as nanofiltration would be necessary for the infiltrated water to be a safe potable supply.

The concentration and loading distribution of trace metals (Cu, Zn, Pb, Co, Ni, Cr, and Mn) and major elements (Al, Ca, Fe, and Mg) in different particle size fractions (2000–280, 280–100, 100–50, 50–10, 10–2, and <2μm) of surface soils from highly urbanized areas in Hong Kong were studied. The enrichment of Pb, Cu, and Zn in the urban soils was strongly influenced by anthropogenic activities, and Pb accumulated in fine particles was mainly derived from past vehicular emissions as shown by Pb isotopic signatures. Trace metals primarily accumulated in clay, fine silt, and very fine sand fractions, and might pose potential health risks via the inhalation of resuspended soil particles in the air (PM₁₀ or PM₂.₅), and ingestion of adhered soils through the hand-to-mouth pathway. The mobility, bioavailability, and human bioaccessibility of Pb and Zn in bulk soils correlated significantly with metal concentrations in fine silt and/or very fine sand fractions.

Intensive land development as a result of the rapidly growing tourism industry in the “Riviera Maya” region of the Yucatan Peninsula, Mexico may result in contamination of groundwater resources that eventually discharge into Caribbean coastal ecosystems. We deployed two types of passive sampling devices into groundwater flowing through cave systems below two communities to evaluate concentrations of contaminants and to indicate the possible sources. Pharmaceuticals and personal care products accumulated in the samplers could only have originated from domestic sewage. PAHs indicated contamination by runoff from highways and other impermeable surfaces and chlorophenoxy herbicides accumulated in samplers deployed near a golf course indicated that pesticide applications to turf are a source of contamination. Prevention and mitigation measures are needed to ensure that expanding development does not impact the marine environment and human health, thus damaging the tourism-based economy of the region.

Due to high availability of adsorption sites, forested catchments could be net sinks for pollutant arsenic both during the period of increasing and decreasing pollution. We tested this hypothesis along a north–south pollution gradient in spruce die-back affected areas of Central Europe. For two water years (2007–2008), we monitored As fluxes via spruce-canopy throughfall, open-area precipitation, and runoff in four headwater catchments (Czech Republic). Since 1980, atmospheric As inputs decreased 26 times in the north, and 13 times in the south. Arsenic export by runoff was similar to atmospheric inputs at three sites, resulting in a near-zero As mass balance. One site exhibited a net export of As (2.2 g ha⁻¹ yr⁻¹). In contrast, the preceding period (1995–2006) showed much higher As fluxes, and higher As export. Czech catchments do not serve as net sinks of atmospheric As. A considerable proportion of old industrial arsenic is flushed out of the soil.

There is currently a requirement for studies focusing on the long-term sustainability of phytoremediation technologies. Trace element uptake by Salix, Populus and Alnus species planted in dredged contaminated canal sediment and concentrations in sediment and pore waters were investigated, eight years after a phytoremediation trial was initiated in NW England. Soil biological activity was also measured using invertebrate and microbial assays to determine soil quality improvements. Zinc was the dominant trace metal in foliage and woody stems, and the most mobile trace element in sediment pore water (∼14 mg l⁻¹). Biological activity had improved; earthworm numbers had increased from 5 to 24, and the QBS index (an index of microarthropod groups in soil) had increased from 70 to 88. It is concluded that biological conditions had improved and natural processes appear to be enhancing soil quality, but there remains a potential risk of trace element transfer to the wider environment.

Underlying levels of atmospheric pollutants, assumed to be governed by smoothing mechanisms due to atmospheric dispersion, can be estimated from global emissions source databases on greenhouse gases and ozone-depleting compounds. However, spatial data may be contaminated with noise or even missing or zero-valued at many locations. Therefore, a problem that arises is how to extract the underlying smooth levels. This paper sets out a structural spatial model that assumes data evolve across a global grid constrained by second-order smoothing restrictions. The frequency-domain approach is particularly suitable for global datasets, reduces the computational burden associated with two-dimensional models and avoids cumbersome zero-inflated skewed distributions. Confidence intervals of the underlying levels are also obtained. An application to the estimation of global levels of atmospheric pollutants from anthropogenic emissions illustrates the technique which may also be useful in the analysis of other environmental datasets of similar characteristics.

This study explores long-term environmental fate of α-HCH in China from 1952 to 2007 using ChnGPERM (Chinese Gridded Pesticide Emission and Residue Model). The model captures well the temporal and spatial variations of α-HCH concentration in Chinese soils by comparing with a number of measured data across China in different periods. The results demonstrate α-HCH grasshopping effect in Eastern China and reveal several important features of the chemical in Northeast and Southeast China. It is found that Northeast China is a prominent sink region of α-HCH emitted from Chinese sources and α-HCH contamination in Southwest China is largely attributed to foreign sources. Southeast China is shown to be a major source contributing to α-HCH contamination in Northeast China, incurred by several environmental factors including temperature, soil organic carbon content, wind field and precipitation.

Development of stress markers for the invader freshwater zebra mussel (Dreissena polymorpha) is of great interest for both conservation and biomonitoring purposes. Gene expression profiles of several putative or already established gene expression stress markers (Metallothionein, Superoxide dismutase, Catalase, Glutathione S transferase, Glutathione peroxidase, Cytochrome c oxidase, the multixenobiotic resistance P-gp1, and heat shock proteins HSP70 and HSP90) were analyzed by quantitative Real-Time PCR in adults and pediveliger larvae after exposure to metals (Hg, Cu, Cd). A defined pattern of coordinated responses to metal exposure and, presumably, to oxidative stress was observed in gills and digestive gland from adults. A similar, albeit partial response was observed in larvae, indicating an early development of stress-related gene responses in zebra mussel. The tools developed in this study may be useful both for future control strategies and for the use of zebra mussel as sentinel species in water courses with stable populations.